Carl S. Gutekunst wrote:
There's another common problem I have, though, that may be more of what
Hector was thinking of. Suppose I have an SMTP receiver that's been down
for a small number of hours, so I'm still within the range where clients
are retrying pretty aggressively. When the receiver comes back up, it
gets swamped with connections, a situation was used to call a "deferral
storm." In this situation, some number of the clients will get 4xy
responses again, while others would be accepted, and the rate of
accept/defer will be likely be tied to the connection rate of the
clients, whether I intended it to be that way or not. Here, what would
be useful is a way to apply controlled back-pressure to the storm.
Lets keep in mind not only server storms but also individual MTA's
storm (accumulated pressure points) created by remote down times
and/or 4yz failures with unknown blocking times. Simple example, on a
normal basis, there are 100 messages from a site to send mail to your
system spread out through the day. Now you are down, and there is
accumulation to send mail to your site.
How should that be done?